Modular tobacco handling and curing system and method

ABSTRACT

A tobacco handling and curing system and method is provided and in one aspect includes a curing container of generally rectangular solid configuration of which four side walls are generally imperforate and a pair of opposed side walls are perforate for the passage of curing gas therethrough. Such container may include one or more perforate interior transverse walls parallel to the opposed walls; adjustable edge baffles for the perforate side walls; and means carried by a pair of imperforate side walls to assist in handling the container. In another aspect of the present invention, novel curing mechanism is provided to receive a plurality of the containers and to direct gas therethrough at predeterminable temperature, humidity and volume.

United States Patent [1 1 Johnson MODULAR TOBACCO HANDLING AND CURINGSYSTEM AND METHOD [75] Inventor: William H. Johnson, Raleigh, NC.

[73] Assignee: Research Corporation, New York,

[22] Filed: Aug. 15, 1973 [21] Appl. No.: 388,590

Related U.S. Application Data [63] Continuation-impart of Ser, No.288,028, Sept. 11,

1972, abandoned.

[52] U.S. Cl. 34/225; 34/196; 34/222;

34/233; 131/134 [51] Int. Cl. F26b 19/00 [58] Field of Search34/195-199,

[ Aug. 19, 1975 Primary Examinerl(enneth W. Sprague AssistantExaminer-James C. Yeung Attorney, Agent, or FirmHarold L. Stowell [5 7]ABSTRACT A tobacco handling and curing system and method is provided andin one aspect includes a curing container of generally rectangular solidconfiguration of which four side walls are generally imperforate and apair of opposed side walls are perforate for the passage of curing gastherethrough. Such container may include one or more perforate interiortransverse walls parallel to the opposed walls; adjustable edge bafflesfor the perforate side walls; and means carried by a pair of imperforateside walls to assist in handling the container. In another aspect of thepresent invention, novel curing mechanism is provided to receive aplurality of the containers and to direct gas therethrough atpredetenninable temperature, humidity and volume.

12 Claims, 24 Drawing Figures ILNIEUAUGYQIQYS MEET 1 OF 8 n n 0 a}... oo o 0 0 2.0 o

3 PATENTED A118 1 9 I975 SJKU 5 OF PATENTED AUG 1 9 I975 NW Qk TOBACCOHANDLING AND CURING SYSTEM AND METHOD MODULAR THE INVENTION Thisinvention relates to a new and improved system for handling and curingtobacco, in either intact or cut strip form, which materially simplifiesthe materials handling problems of tobacco harvesting and curing.

It is a particular object of the present invention to provide curingcontainers or modules which receive either intact or cut strip tobaccoand once the containers or modules are filled, the tobacco itself is notphysically handled by operators or machines until the tobacco is fullycured or cured and conditioned.

It is an object to provide such containers or modules which includemeans for controlling the flow of curing gases through the tobacco andmeans for facilitating the machine handling of the modules.

It is a further object to provide a means or system for handling andcuring of large batches of tobacco in specially constructed containersor modules, each of which may hold up to, for example 1500 or morepounds of tobacco.

Another object is to provide a module which includes features ofrotatability for orientation of the tobacco after filling and ease ofunloading after curing and screen dividers for support of the tobaccoand to permit curing airflow therethrough;

A further object is to provide such a module which lends itself tomechanical handling by conventional handling vehicles such as forklift,tractor lift, or other mechanical aids.

Another object is to provide a system including a module which can bedirectly filled from mechanical harvesting apparatus and transported toa curing site.

In another aspect of the present invention it is an object to provide animproved curing station which receives a plurality of the filled moduleswhich station includes means to urge forced air, which is heated andrecirculated, through the modules as required to thereby materiallyimprove the uniformity of the product, reduce hand labor, curing timeand ultimately the cost of tobacco production.

It is another object to provide such a module curing station whichincludes a special foundation structure which serves as an air supplyplenum, curing modules which seal directly with the foundation, a topair plenum which may lower, tilt or raise or have means between thelower surface thereof and the curing modules to permit insertion andremoval of the modules to seal or unseal with the top portion of themodules and a forced air heating and/or humidifying unit which connectswith both the top and the bottom plenums.

These and other objects and advantages will become apparent to thoseskilled in the art from the following detailed description of thepresent invention when considered in light of the accompanying drawingswherein:

FIG. 1 is a perspective exploded view partially in section of a tobaccocuring module constructed in accordance with the teachings of thepresent invention;

FIG. 2 is an elevational view of a form of tobacco curing stationincluding six of the modules such as illustrated in FIG. 1;

FIG. 3 is a top plan view of the structure shown in FIG. 2;

FIG. 4 is the right end view of the structure shown in FIGS. 2 and 3;

FIG. 5 is an elevational view of a module transporting vehicle with twomodules received thereon;

FIG. 5a is a top plan view of the structure shown in FIG. 5 without themodules;

FIG. 6 is a side elevational view of a conventional fork lift vehiclemodified to handle modules constructed in accordance with the presentinvention;

FIG. 6a is a further view of the structure shown in FIG. 6; 7

FIG. 7 is a partially diagrammatic view of a modified form of a curingstation;

FIG. 8 is a view similar to FIG. 7 of another form of curing station;

FIG. 9 is an elevational view of another form of curing station;

FIG. 10 is an elevational view of still a further form of curingstation;

FIG. 11 is a perspective exploded partially sectional view of a modifiedform of curing module constructed in accordance with the presentinvention;

FIG. 12 is a perspective exploded partially sectional view of a furthermodification of the curing module;

FIG. 13 is an enlarged fragmentary view of a portion of the slidablebafi'les illustrated in conjunction with the module shown in FIG. 12;

FIG. 14 is a perspective view of a modified form of the module;

FIG. 15 is a perspective view of a further form of the module of thepresent invention;

FIG. 16 is a section on line l6l6 of FIG. 15;

FIG. 17 is a partially diagrammatic view of a modified form of a curingstation;

FIG. 18 is an end elevation of the structure shown in FIG. 17;

FIG. 19 is a section on line I9l9 of FIG. 17;

FIG. 20 is a partially diagrammatic end view of a further form of acuring station;

FIG. 21 is a view like FIG. 20 showing a loading or unloading positionof the illustrated structure; and,

FIG. 22 is a view like FIG. 21 showing another filling position of thestation.

Referring now to the drawing and in particular to FIG. 1, 10 generallydesignates one of the containers or modules for the curing of tobacco inaccordance with the teachings of the present invention. The module 10includes imperforate sides 12, I4, 16 and 18, and perforate sides 20 and22. In the illustrated form of the invention the module 10 or containeris cubicle in configuration and a module of 4 X 4 X 4 feet insidedimensions, is designed to hold from about 900 to about 1500 pounds ofuncured tobacco leaf with an empty container weight of about 300 toabout 500 pounds. The total weight of a filled container of saiddimensions would be about 1200 to 2000 pounds. A module having 5 footinternal dimensions when filled with tobacco would weigh approximately 1to 1.5 tons when the module is of predominantly wooden construction withmetal screens in the side wall 20 and 22 and with a screened centerpartition generally "designated 24.

Each of the imperforate side walls 12, 14, 16, and 18 is formed with ametal or wooded peripheral frame 26 and a panel 28 of plywood orpreferably each ofthe imperforate walls of the module is constructed ofdouble layer of plywood 19 and 21 spaced by insulation 23. Theinsulation is preferably of rigid foam material such as Styrofoam whichhas excellent insulating properties with substantial resistance tocompression. The side walls 12, 14, and 16 are rigidly and integrallyformed with side walls 20 and 22 whereas side wall or cap 18 isremovable as illustrated in FIG. 1. After the module is filled the sidewall 18 is secured to the other side walls of the container by aplurality of studs 32 anchored in the peripheral wall 30. The studs arereceived in bores 34 in the peripheral edge of wall 18 and securedthereto by suitable wing nuts or the like. It will also be appreciatedby those skilled in the art that in place of the studs 32 andcooperating wing nuts other.

separable fastening means may be employed with the module of theinvention. Furthermore, the side wall 18 may be hinged onone side toeffect closure of the module as to be described in reference to FIG. 14.

The ends walls 20 and 22 and the partition wall 24 are, as hereinbeforedescribed, perforated and in the illustrated form of the invention thewalls comprise expanded metal screening having a high ratio of openspace to metal. The primary function of the expanded metal screen 36 isto retain the tobacco leaves in whole or in cut strip form within thecontainer during subsequent handling and during the curing stage whilepermitting substantial volume flow of heated treated gases to passtherethrough with a minimum of resistance.

As to be further described hereinafter the perforated walls may compriseperforated metal, expanded metal, plastic or metal ribs formed toprovide parallel ridges and valleys, etc.

As hereinbefore set forth, in view of the weight of even the relativelysmall modules of the 4 X 4 X 4 feet type, the module 10 includes a luggenerally designated 40 on each of the side walls 12 and 16. The lugs 40are retained on the side walls by a pair of angle irons 42 and 44 whoseprimary function is to distribute the weight of the load throughout thecarrying side walls. Further, it will be noted that the lugs 40 includeend plate members 44 which, as to be more fully described, cooperatewith lifting slings 46, FIGS. 6 and 6a, provided with shaped openings 48which are slipped over the end plates 44 and securely engage the shaftportions 50 thereof.

In FIGS. 6 and 6a, the carrying rings 46 are chain connected to a pairof side-by-side horizontal arms 52, secured to the lifting face 54 of aconventional forklift vehicle generally designated 56. Each of thehorizontal support arms 52 is suitably braced as to 58 whereby themodules 10 may be readily moved from their filling stations tosupplemental hauling means to be described in reference to FIGS. and 5a,and placed and or turned and stacked in the curing station as to be morefully described in reference to FIGS. 2 through 4, and 7 through 10. a

Referring to FIGS. 5 and 5a where the filling of the module is remotefrom the curing station, the modules may be transported between theharvester and/or leaf slicer and the curing station on small tractordrawn dollies generally designated 70. The dolly 70 includes a platform72 forming a-flatbed to receive a pair of the modules, which platform issuitably rotatably mounted via axle 74 and wheels 76. The flatbed'of thedolly may comprise a plurality of elongated rollers generally designated78, which rollers are mounted in banks of pairs designated A and B sothat the modules 10 can be simply rolled from the dolly into theassigned spaces at the curing station. In order to anchor the modules onthe dolly bed a crossbar for each section A and B is provided with endrecesses 82 which are adapted to receive stop pins 84 after the modulesare positioned on the dolly.

Referring now particularly to FIGS. 2 through 4, one of the novel curingstation forming one aspect of the present invention is generallyillustrated at 100. In these figures the curing station is adapted toreceive six of the modules 10 in two rows of three. The curing stationincludes a foundation generally designated 1 10 which is built toprovide a pair of air channels 112a and 11212 which are open in the zoneof each of the modules as shown in the broken section of FIG. 3 of thedrawings. At end 114 of the curing station is mounted a furnacegenerally designated 116. The furnace includes a burner or heater 118, adraft creating means such as motor-driven fan 120, and a humidifier 122.Above the modules 10 and the furnace 116 is an upper plenum chambergenerally designated 124. Theupper plenum chamber 124 is suspended froma frame 126, which frame includes corner posts 128 and longitudinal andtransverse cross-members 130 and 132, respectively. The transversemembers 132 carry on their under surfaces shafts 134 suitably rotatablymounted in bearings 136 adjacent one of the longitudinal runners 130 andin the center and suitable drive means along the opposite sidesgenerally designated 140. The shafts 134 carry pulleys or shives 142over which are trained flexible draft members 144 having their extendedends connected to the top portion of the upper plenum chambers 124 as at146. By means of the shafts 134, the pulleys 142, the flexible draftmembers 144 and suitable motive means, the upper plenum chamber may beraised and lowered as illustrated by the directional arrow C, FIGS. 2and 4 of the drawings.

About each of the generally rectangular openings formed in the upper andlower plenum chambers a suitable gasketing material 133 is mounted, suchas, inch X 4 inches rubber. The gaskets 133 seal each module between theupper and lower plenums. With six modules positioned as shown in FIGS.2-4 it is not difficult to develop a static pressure up to 4 inches ofwater with negligible air leakage. The top surface of the lower plenumin the zone to receive the module 10 may be formed as open slat worksuch as illustrated at 121. The open slat work 121 may comprise spacedrollers such as previously described in reference to FIG. 5 whereby themodule may be directly rolled from the transporting dolly 70 intoposition on the lower plenum chamber.

In FIGS. 2 and 3, the upper plenum chamber 124 is in its elevatedposition to thereby permit insertion of the modules 10 or removal orrotation thereof. Once the modules 10 are in the desired position theupper plenum chamber is lowered so that there is a closed flow path forthe heated and/or heated and humidified curing air as illustrated by thedirectional arrow. The upper plenum chamber is also provided withsuitably controllable outlet dampers in the side walls as illustrated at150, and an inlet damper in the end wall as illustrated at 152 whereby aportion of the circulated air may be exhausted through dampers 150 andmake up air may be added at damper 152.

The damper system also includes a recirculation damper 153 which isconnected to damper 152 by control rod 155 so that as one opens theother closes. The outler dampers 150 are preferably of the gravityvanetype which open or close due to changes in the static pressure in theplenum, due to changes in positioning of the recirculation damper 153.

In operation of the curing stations as shown in FIGS. 2, 3, and 4, sixmodules filled with tobacco are positioned as shown with the open screensides being in register with the upper and lower plenum chambers 124 and110. After a suitable time of curing as to be more fully described theupper plenum chamber 124 may be raised and each of the modules may berotated 180 so that the original open top portion of the module is inthe downward position. This rotation serves to speed the curing and atthe same time improves the uniformity of the finished product.

A modified form of curing station is illustrated in FIG. 7 and generallydesignated 100a. The curing station 100a includes upper plenum 124a andlower plenum 110a and a furnace section 116a. The lower plenum 1100includes a plurality of outlet dampers 150a and an inlet damper l52awhich elements correspond to their complementary elements in FIG. 2. Thetop plenum 124a is also suspended for vertical movement on a frame 126as in the form of the invention shown in FIGS. 2, 3 and 4. In this formof the invention the direction of flow of air from the furnace 1 16a isopposite to that shown in FIGS. 2, 3, and 4. It is also contemplatedthat a reversible motor may be provided for the draft means 120, FIG. 2,and 120a, FIG. 7, so that during a portion of the cycle air is passed inone direction through the modules and during the other half of thedrying cycle air is passed in a reverse direction of flow. Using thereverse direction of flow method of operation has the similar advantageto that of rotating the module 10 180 during curing. However, using thereverse flow of curing gas movement complicates to some extent theoperation of the dampers 150, 150a, 152, l52a and the recirculationdampers, 153 and 153a.

Referring to FIG. 8, another fonn of the curing station is illustratedand generally designated 100b. In this form of the invention there isprovided a lower plenum chamber l10b similar in construction andfunction to the lower plenum chamber 100, FIGS. 24, and an upper plenumchamber 124b, also similar in structure and function to that illustratedin FIGS. 2-4. A furnace 1l6b is provided at end 11412 and the upperplenum chamber l24b is suitably supported from the framework 126bwhereby the upper plenum chamber l24b may be raised and lowered. Theprimary distinction between this form of the invention and thatillustrated in FIGS. 2-4 is in the height of the furnace 116b, whichheight is sized to permit stacking of two rows C and D of modules 10 toeither reduce the width of the curing station or to double its capacityfor the same ground area.

The upper plenum is provided with flow control dampers 150b, l52b and153b as in the other described form of my invention.

Referring to FIG. 9 a modified curing station 1006 is illustrated and inthis form of the invention the upper plenum chamber 124a is formed astwo sections 160 and 162. Section 160 is immovably mounted to the upperend of the furnace 1166 while the section 162 is suitably mounted fromthe framework 126( for vertical lifting movement whereby the module 10may be suitably placed on top of the lower plenum chamber 1106. Section160 and 162 of the upper plenum chamber 1246 are connected by anaccordion-type expansible joint generally designated 164.

Referring now to FIG. 10, a further curing station d is shown. In thisform of the invention the upper and lower plenum chambers 124d and d,respectively are arranged such that the furnace and draft creating means116d is mounted in the center and flow of curing gases is controlled bydampers 166, 168, 170 and 172 in addition to inlet damper 152d andoutlet damper d. The first pair of dampers is mounted in the upperplenum chamber 124d and the second pair in the lower plenum chamber110d. Two banks of containers or modules 10 rest on the lower plenum andconnect with suitable passages in the upper plenum so that gas flowthrough this device is as illustrated by the directional arrows. Inaddition to being able to handle a substantial number of curing modules,this form of the invention also has the added feature that by, forexample, closing dampers 166 and 170, only half of the unit may beemployed during the nompeak production times.

Referring now to FIG. 11, a modified form of module is illustrated at10a. In this form of the invention the module includes the gasimpervious side walls 12a, 14a, 16a, and 18a constructed as shown anddescribed with reference to FIG. 1. Further, this form of the inventionalso includes gas pervious side walls 20a and 22a corresponding to walls20 and 22 of the FIG. 1 form of the invention. The module 10a differsfrom the module 10 in that a pair of parallel gas pervious walls 240 and24b are mounted within the module parallel to the gas pervious walls 20aand 22a. The gas pervious interior walls 24a and 24b divide the spacewithin the module into three compartments. Dividing the module into agreater number of compartments reduces packing of the tobacco duringhandling and assists in insuring a more uniform airflow through thedevice. As in the previous form of the invention, handling lugs 40a areprovided on each of the side walls 12a and 16a.

It has been found in use of the modules constructed in accordance withthe present invention that as the tobacco loses moisture it shrinks inbulk and in some cases the shrinkage occurs greatest along one of theimperforate walls thus increasing the time required to fully cure thetobacco. This sneakage of gas along an imperforate wall may becontrolled by the installation of baffles along the peripheral marginsof the gas pervious screen walls. A module constructed in this manner isillustrated in FIGS. 12 and 13. In FIGS. 12 and 13 the module 10bincludes imperforate walls 12b, 14b, l6b,

.and 18b, with walls 12b and 16b being provided with handling lugs 40bas previously described in reference to FIGS. 1 and 11. Further, themodule includes gas pervious open-mesh screened end walls 20b and 22band interior perforate partition wall 24b. Each of the open-meshscreened walls 20b, 22b, and 24b are provided about their peripheraledges with metal, wood, or plastic baffle members 200, more clearlyshown in FIG. 13. The baffles 200 are secured to the margins or frames26b by means of screws or other anchor-type fasteners generallydesignated 202. The fasteners 202 pass through elongated slot-likeopenings 204 in the baffles which permit the baffles to be moved in thedirection of the directional arrows E, FIG. 13, to thereby regulatewithin limits the area of the screens to be blocked by the baffles. Ithas been found that after the tobacco has partially dried bafflesextending inwardly, for example, 3 to 8 inches, provide greater controlof gas sneakage along imperforate walls and by means of the slidable andadjustable baffles 200 this control may be readily available to theoperator.

Referring now to FIG. 14, a modified form of module is illustrated at10b. In this form of the invention the module includes the gasimpervious side walls 12b, 14b, 16b, and 18b constructed as shown anddescribed with reference to FIG. 1, except that wall 18b is hinged toone of the other side walls. Further, this form of the invention alsoincludes gas pervious side walls 20b and 22b corresponding to walls 20and 22 of the FIG. 1 form of the invention, and parallel gas perviouswall 24b mounted within the module parallel to the gas pervious walls20b and 22b. The gas pervious walls 20b, 22b and 24b are formed withspaced parallel bars, ribs or rods 300 instead of screen or expandedmetal 36 as in FIG. 1 of the drawings. The bars run vertically such thatthey are perpendicular to the general plane of the tobacco leaves or cutstrips. The bars give less resistance during packing, and hence lessfolding of lamina. Furthermore, when the module is rotated by 90, thetobacco can distort and settle slightly between the bars to provideincreased opening for air movement into the tightly packed tobacco. Bydecreasing this interfacial resistance between the tobacco and thesupport screen, even further advances can be made in loading capacitieswith high efficiency and uniformity of drymg.

Spacing of the parallel bars should be such that the material isadequately supported with minimal slippage or loss between the bars. Forexample, with 3 inch X 3 inch strips, a spacing of about 1.5 inchesbetween the bars should be satisfactory. For intact random leaves, aspacing of about 3 to 6 inches should adequately support the material,of course, depending upon tobacco type.

Referring now to FIGS. and 16 a further modified form of module isillustrated at 10c. In this form of the invention the module includesthe gas impervious side walls 120, 14c, 16c, and 180 constructed asshown and described with reference to FIG. 1. Further, this form of theinvention also includes gas pervious side walls 200 and 220 and parallelpartition wall 240 corresponding to walls and 22 of the FIG. 1 form ofthe invention. The module 10c differs from the module 10 in that theinner peripheral edges of the strips 200C carrying the screen 360 andagainst which the weight of the tobacco bears when the module is rotatedare provided with inwardly curved, integral lips 302. The edges of thelips thus bear perpendicularly against the tobacco leaves when thecontainer is rotated 90 during tobacco curing and thus assist indirecting air flow through the tobacco.

A modified form of curing station is illustrated in FIGS. l7, l8 and 19and generally designated 300. The curing station 300 includes upperplenum 302 and lower plenums 3040, b and c and a furnace section 306.The upper plenum 302 includes a return air damper 308 and an inletdamper 310 which elements correspond to their complementary elements 152and 153 in FIG. 2 and the dampers are interconnected by a control rod312. The top plenum 302 is supported on a frame 314 in spaced relationto the modules 10. The upper plenum is rigidly connected to the top ofthe furnace 306 and flexibly connected to the tops of modules by sidecurtains 316 and end curtains 318. The end curtain 318 adjacent end 320is mounted for folding or rolling such as by ropes and pulleys 322 and324 so that the modules 10 may be placed on the lower plenums in thedirection of directional arrow A. Air is circulated from the furnace 306via fan or blower 318 to the lower plenums 3040, b, and c and upwardthrough the modules 10. A high static pressure of 2 or 3 inches (watercolumn) is maintained in the bottom plenums, with the modules sealingtightly against gaskets over the plenum structures. In the illustrationof FIGS. 17, 18 and 19, a means is shown whereby the modules may beeasily moved into position for curing, with the tops of the moduleslocated beneath a hood or curtain 316-318. The hood or curtain may beconstructed of canvas, or other suitable material.

The rationale for not having a completely sealed connection is that theupper plenum, with air movement as shown by the directional arrows, isnear atmospheric pressure or slightly above. During the yellowing phaseto the tobacco, the inlet damper 310 is closed and the recirculationdamper 308 is open. High humidities are maintained as the air from themodules rises within the hood and upper plenum and recirculates withinthe system. During drying, the inlet damper 310 is opened as required,which in turn closes recirculation damper 308. This establishes a smallpositive pressure in the upper plenum 302 and hood 316-318 such that airis discharged around the base of the hood as shown at 330. Furtherrecirculation during the latter stages of drying is accomplished byclosing damper 310 and opening damper 308. The hot air from the modulesrises within the hood to recirculate back to the furnace.

Further in this design, the bottom plenum 304a, b and c are constructedbeneath the ground, and may be formed with concrete side and end walls.The plenums are shown constructed with the top of the plenum flush witha concrete pad 332 such that the modules may be moved by forklift intocuring position.

In FIG. 3, the sectional view illustrates the bottom plenum layout. Thisparticular arrangement allows flexibility in number of lateral bottomplenums, with three laterals shown. The modules may be moved intoposition from the end, as shown by the arrows A, with forklift or othersuitable mechanism. Metal grids 334 cover the plenums to permit drivingdirectly over the plenums. Bridging plates 336 are provided to permitsealing of the modules with respect to the bottom plenums.

Referring now to FIGS. 20, 21 and 22, a further modified form of theinvention is illustrated. In this particular embodiment, the curingmodule 400 is hinged to the bottom plenum structure such that it can betilted outwardly with respect to the bottom plenum and foundation. Thisfeature is desirable in the event very large modules (e.g., 6 X 6 X 6feet or 8 X 8 X 8 feet) become practical for filling directly at thecuring station. At current packing densities of 18 lbs. green weight percubic feet, an 8-foot cube will hold approximately 9200 pounds oftobacco per cure. At such size, more likely the packing density would be20 lbs/ft. (10,240 lbs.), which would cure 5 acres of tobacco perseason. An 8-ft. cube is equivalent in volume to eight 4-ft. cubes.Also, the very appreciable reduction in size of curing facility incomparison with conventional or bulk barns becomes very apparent.

This particular embodiment could, of course, be used with smallermodules and multiple modules on the same bottom plenum.

In FIG. 20, a side elevational view of a curing facility incorporating amodule hinged to the bottom foundation plenum is illustrated. This isscaled to approximate an 8-ft. module 410 having four compartments 412a,b, c, and d for holding the tobacco. The basic design and operationprinciples are very much as presented hereinbefore. The top plenum 414is shown hinged at the left bottom as at 416. When in the loweredposition, the top plenum seals against the top of the module 410. Thetop plenum 414 is tilted about its hinge or pivot 416 via, for example,a cable or cables 418 and suitable cable takeup means not shown. The topplenum, as shown, is hinged to the furnace and blower combination 420which may be like furnace 306 of the form of the invention shown inFIGS. l7, l8 and 19. The hot gas outlet from the furnace is into bottomplenum 422 and the upper plenum is provided with suitable dampers 424,426 and 427, each of which functions as hereinbefore described withreference to other station embodiments.

FIG. 21 illustrates the manner of tilting the module 410 outwardly forunloading and refilling. A top support structure 430 with lift enableslifting of the top plenum to permit tilting outwardly of the module. Theentire top plenum could be raised but this is not necessary, since onlyclearance for module rotation is required. The hydraulic cylinder 432 ismounted via mounts 434 to the bottom foundation plenum or suitablemounting such that it can exert force to tilt the module, via thecylinders ram 436 which is pivotally connected as at 438 to module 410,into the position shown in FIG. 21, so that when module doors 440 areopened on the right side of the module allow the tobacco to fall fromthe compartments. The cured tobacco can be collected in sheets orsuitable containers. A conveyor also may be rolled beneath the tiltedmodule to receive the tobacco and convey the material to a suitablecontainer for market.

FIG. 22 illustrates the position of the module 410 for filling. In thisposition, the hydraulic cylinder 432 has moved the module into itsoutermost position and the perforate partitions are vertically oriented.One or more doors 442, now on the top side of the module, are opened toreceive tobacco into the vertical compartments. Doors 440 on the bottommodule side are closed. Tobacco can be loaded into the module with anoscillating distributor which moves above the module compartments and anextension sleeve may be set into position over each compartment topermit overfilling prior to compressing the tobacco into the modulecompartment. A suitable elevator with oscillating distributor conveysthe material upwardly and deposits it into the compartments, and theelevator-distributor (not shown) could be shifted in position to fillcompartments consecutively. After filling the material can behand-packed with a press board or with a mechanical press which also canbe positioned over each compartment. The top doors 442 (or covers) arenow closed and the filled module is moved into the curing position ofFIG. 20 by means of the hydraulic cylinder. The top plenum is loweredand the material is ready for curing. During filling, compressing, etc.,of the tobacco, the

module is supported at its extended edge via fixed or movable supportmember 450.

From the foregoing description of specific embodiments of the presentinvention, it will be seen that the aims and objects hereinbefore setforth are fully accomplished, to thereby provide a method and apparatusfor full modular handling and curing of tobacco which greatly simplifiesthe materials handling problems and offers to the industry a furtheropportunity for labor and cost reductions.

In use of the system of the invention, either cut strip or intacttobacco leaves are packed into the compartments, container, or module,to a loading density of about, for example, 14 to 20 pounds per cubicfoot. With the compartmented form of construction tobacco leaves orstrips will normally assume generally horizontal positions when allowedto freefall into the module. Whole oriented leaves may also be easilyhand-packed into the module, preferably with the butts (petioles)resting against the perforate wall or screen supports, such that thebutts provide substantial support for the lamina when the module iscapped and rotated by for curing. After the module is filled the cap orremovable end wall is secured to the module. After capping the module isreadily rotated 90 in the vertical plane by means of the rods locatednear the centers of opposed nonperforate side walls of the module. Afterrotating, the screens or air pervious walls of the module are positionedin a horizontal plane to permit vertical movement of forced air betweenthe leaves or strips which due to rotation are now in the vertical mode.g

The filling may be such that orientation of the tobacco within thecontainer is intact random, oriented with butts resting on the perforatewalls, and cut-strip with the general plane of the lamina vertical whenin the position for curing.

The filled, capped and rotated modules are then sent to a curing stationwhich, in the preferred form of the invention, would be the curingsystem shown in FIGS. 2 through 4, 7 through 10, and 17 through 22;however, the modules may be placed in conventional bulk curing barns inplace of the usual racks. Assuming the use of the curing system of thepresent invention, six filled modules are positioned on the lowerplenum. Position-' ing of the modules on the lower plenum may be carriedout by means of the forklift device shown in FIGS. 6 and 6a. With thetop plenum lowered, tilted or otherwise sealed around the top of eachmodule and the furnace to give a continuous passage for recirculatingair substantially without leakage.

As hereinbefore discussed, the top plenum also includes inlet,recirculation and exhaust dampers which are used in controlling humidityconditions during curing. With the inlet damper open and recirculationdamper closed, fresh air is drawn into the furnace,

- forced upwardly through the tobacco and discharged through the lowerventilator. With the inlet damper closed and the recirculation damperopen, air recirculates to establish high humidity. At various stagesduring curing the inlet and recirculation dampers may be adjusted over arange of settings to establish the desired humidity for curing.

In a prototype a fan associated with the curing station furnace wasselected to deliver about 1.5 cubic foot per minute per pound of uncuredtobacco at a static pressure of approximately two to three inches watercolumn. Thus, with six modules containing, for example,

6000 pounds of uncured tobacco theblower or fan should deliver fromabout 6000 to 9000 cubic feet per minute at about two inches of waterstatic pressure. Under these circumstances the furnace should deliverapproximately 250,000 BTUs/hour for satisfactory drying at the maximumdrying stage and the furnace may be of the direct fired gas or indirectfired oil burner types.

Since it has been found that certain problems frequently encounteredduring tobacco curing such as bacterial decay occur near the top ofcuring barns and tobacco yellows unevenly with the yellowing occurringfaster where the air is introduced, the curing module may be rotated attimely stages during curing to provide for more uniform yellowing,drying, and conditioning.

As hereinbefore described, the loading density of tobacco for themodules will vary with the size of the tobacco material loaded thereinand the size of the module; hence, it is recommended that while 14through 20 pounds per cubic foot density would probably be optimum, arange of from about pounds to about 25 pounds per cubic foot would befunctional.

While it is not an object of the present invention to provide optimumcuring cycle parameters, the following schedule will produce verysatisfactorily cured tobacco (for flue-cured type). After the tobaccohas been placed in the curing station the fan is energized and thethermostat set for coloring, that is, yellowing, at about 90 to 105 F.The dampers are adjusted for essentially complete recirculation of theair. If the tobacco is wet the surface water may be removed by ventingto the outside for several hours. During this coloring phase the tobaccoleaf turns yellow as chlorophyl is oxidized, unmasking the yellowpigments of the plant. Important biochemical changes also occur duringthis phase, including starch hydrolysis and proteolysis. This period ofcure generally requires from about 30 to about 72 hours depending onleaf position and maturity at harvest.

After this first phase the temperature within the curing chambers isgradually increased at about 2 to 3 F. per hour until reaching about 130to 135F. This temperature is maintained until the majority of lamina isdried. During this time the humid air is exhausted by gradually openingthe intake dampers while closing the recirculation damper. After laminadrying the temperature is then increased at about 2 to 5 F per houruntil reaching about 170F. where final stem drying occurs. Final leafand stem drying under the conditions set forth above requires about 2 to3 days so that the total yellowing and drying may require from about 4to 6 days. It is also recommended that at the latest stages of curingthat the intake damper of the curing station be adjusted to a nearclosed position to permit a high percentage of air recirculation tothereby conserve fuel.

Following curing, the tobacco may be brought into condition, that is,remoistened to to 18 percent moisture by opening the ventilators andcirculating outside air through the tobacco or by injecting moistureinto the air via the humidifier in the heater section, as shown in thedrawings. Following conditioning, the tobacco is then ready forpreparation for market and the module may be readily unloaded by merelyremoving the cover or cap and rotating then so that the removable coveror cap is in a downward direction.

While the above operating procedure has been described for tobacco ofthe flue-cured type, it is apparentthat the system may be used forcuring other tobaccos such as Burley, Maryland, cigar tobacco, Oriental,etc., by simple modification of temperature-time schedules.

Further while the present invention has been developed primarily fortobacco curing, it is recognized that other crops could'be dried usingthe identical system. Said other crops may include sweet potatoes,peanuts, corn, tea leaves, onions, grain, fruits, and vegetables, etc. I

I claim:

1. A curing station for tobacco curing modules, the modules havingclosed sidewalls and top and bottom walls open for the passage of gasthrough the modules substantially from sidewall to sidewall thereof,comprising a generally horizontal foundation, plural openings in theupper surface thereof each sized tofedge support a curing modulethereover, and said plural openings in said uppersurface beingcoextensive with the open top and bottom walls of .the tobacco curingmodules, a further opening in the upper surface, a hot air furnace meanssupported over the said further passage of heated gases there-between, atop plenum.

chamber substantially coextensive with the orizontal foundation, meansassociated with the top plenum chamber providing sealing engagement withthe top of the hot air furnace andthe tops of modules supported on thefoundation and air passages in the top plenum chamber connecting the hotair furnace and the tops of the modules, plural openings in the topplenumvchamber coextensive in number with the numberof curing modulesand coextensive in size with the top openings in the modules, wherebyair from the hotair furnace flows through the gas passages thenuniformally substantially vertically from sidewall to sidewall througheach of said modules and said top plenum chamber.

2. The invention defined in claim 1 including gas flow control dampersin said foundation.

3. The inventiondefined in claim 1 including gas flow control dampers insaid top plenum.

4. The invention defined in claim 1 wherein the hot air furnace means ispositioned at one end of the foundation.

5. The invention defined in claim 1 wherein the said hot air furnacemeans is positioned intermediate the ends of said foundation.

6. The invention defined in claim 1 including gas humidifying meansmounted in said hot air furnace means.

7. The invention defined in claim 1 wherein the means associated withthe top plenum chamber providing sealing engagement with the top of themodules includes means for vertically moving the top plenum chamber intoand out of sealing engagement.

8. The invention defined in claim 1 wherein the means associated withthe top plenum chamber providing sealing engagement with the top of themodules includes curtain means about the lower surface of said topplenum.

9. The invention defined in claim 1 wherein the means associated withthe top plenum chamber providing sealing engagement with the top of themodules includes means for pivoting the top plenum into and out ofsealing engagement.

10. The invention defined in claim 9 further including means forpivoting the curing module into and out of sealing engagement with thelower plenum chamber.

11. A curing or drying system for tobacco comprising a container ofgenerally rectangular solid configuration comprising two pairs ofopposed generally imperforate sidewalls and a pair of opposed sidewallsopen for the passage of curing or drying gas therethrough substantiallyfrom imperforate sidewall to imperforate sidewall of the container, atleast one interior transverse perforate wall parallel to the opposedopen sidewalls with the opening in the transverse wall substantiallycoextensive with the opening in said open sidewalls, means releasablysecuring one of the opposed open sidewalls to the others to thereby forman access opening for the container, a curing station for a plurality ofsaid curing containers comprising a generally horizontal foundation,plural openings in the upper surface thereof each sized to edge supporta said curing container thereover and each of said plural openings insaid upper surface being at least coextensive with the openings in theopen sidewalls of the container, a further opening in the upper surface,a hot air furnace means supported over the said further opening, gaspassages in the foundation connecting the plural openings and the saidfurther opening for the passage of heated gases therebetween, a topplenum chamber substantially coextensive with the horizontal foundation,means mounting the top plenum chamber for sealing engagement with thetop of the hot air furnace and the tops of said containers supported onthe foundation and air passages in the top plenum chamber connecting thehot air furnace and the tops of the said containers, plural openings inthe top plenum chamber coextensive in numer with the number of curingcontainers and coextensive in size with the top openings in thecontainers, whereby air from the hot air furnace flows through the gaspassages then uniformally substantially vertically from sidewall tosidewall through each of said containers and said top plenum chamber.

12. The invention defined in claim 10 wherein the spacing between thefoundation and said top plenum is such as to accomodate a stacked pairof said modules.

1. A curing station for tobacco curing modules, the modules havingclosed sidewalls and top and bottom walls open for the passage of gasthrough the modules substantially from sidewall to sidewall thereof,comprising a generally horizontal foundation, plural openings in theupper surface thereof each sized to edge support a curing modulethereover, and said plural openings in said upper surface beingcoextensive with the open top and bottom walls of the tobacco curingmodules, a further opening in the upper surface, a hot air furnace meanssupported over the said further opening, gas passages in the foundationconnecting the plural openings and the said further opening for thepassage of heated gases there-between, a top plenum chambersubstantially coextensive with the orizontal foundation, meansassociated with the top plenum chamber providing sealing engagement withthe top of the hot air furnace and the tops of modules supported on thefoundation and air passages in the top plenum chamber connecting the hotair furnace and the tops of the modules, plural openings in the topplenum chamber coextensive in number with the number of curing modulesand coextensive in size with the top openings in the modules, wherebyair from the hot air furnace flows through the gas passages thenuniformally substantially vertically from sidewall to sidewall througheach of said modules and said top plenum chamber.
 2. The inventiondefined in claim 1 including gas flow control dampers in saidfoundation.
 3. The invention defined in claim 1 including gas flowcontrol dampers in said top plenum.
 4. The invention defined in claim 1wherein the hot air furnace means is positioned at one end of thefoundation.
 5. The invention defined in claim 1 wherein the said hot airfurnace means is positioned intermediate the ends of said foundation. 6.The invention defined in claim 1 including gas humidifying means mountedin said hot air furnace means.
 7. The invention defined in claim 1wherein the means associated with the top plenum chamber providingsealing engagement with the top of the modules includes means forvertically moving the top plenum chamber into and out of sealingengagement.
 8. The invention defined in claim 1 wherein the meansassociated with the top plenum chamber providing sealing engagement withthe top of the modules includes curtain means about the lower surface ofsaid top plenum.
 9. The invention defined in claim 1 wherein the meansassociated with the top plenum chamber providing sealing engagement withthe top of the modules includes means for pivoting the top plenum intoand out of sealing engagement.
 10. The invention defined in claim 9further including means for pivoting the curing module into and out ofsealing engagement with the lower plenum chamber.
 11. A curing or dryingsystem for tobacco comprising a container of generally rectangular solidconfiguration comprising two pairs of opposed generally imperforatesidewalls and a pair of opposed sidewalls open for the passage of curingor drying gaS therethrough substantially from imperforate sidewall toimperforate sidewall of the container, at least one interior transverseperforate wall parallel to the opposed open sidewalls with the openingin the transverse wall substantially coextensive with the opening insaid open sidewalls, means releasably securing one of the opposed opensidewalls to the others to thereby form an access opening for thecontainer, a curing station for a plurality of said curing containerscomprising a generally horizontal foundation, plural openings in theupper surface thereof each sized to edge support a said curing containerthereover and each of said plural openings in said upper surface beingat least coextensive with the openings in the open sidewalls of thecontainer, a further opening in the upper surface, a hot air furnacemeans supported over the said further opening, gas passages in thefoundation connecting the plural openings and the said further openingfor the passage of heated gases therebetween, a top plenum chambersubstantially coextensive with the horizontal foundation, means mountingthe top plenum chamber for sealing engagement with the top of the hotair furnace and the tops of said containers supported on the foundationand air passages in the top plenum chamber connecting the hot airfurnace and the tops of the said containers, plural openings in the topplenum chamber coextensive in numer with the number of curing containersand coextensive in size with the top openings in the containers, wherebyair from the hot air furnace flows through the gas passages thenuniformally substantially vertically from sidewall to sidewall througheach of said containers and said top plenum chamber.
 12. The inventiondefined in claim 10 wherein the spacing between the foundation and saidtop plenum is such as to accomodate a stacked pair of said modules.